From exposures to mitigation strategies: Assessing complex contaminant mixtures in wastewater and drinking water

Prof. Carsten Prasse
Department of Environmental Health and Engineering
Johns Hopkins University

Drinking water and wastewater treatment systems designed to mitigate chemical exposures are challenged in their efficacy by the increasingly complex chemical mixtures present in source waters due to an expanding list of over 100,000 chemicals in commercial use worldwide. Engineered and natural processes can further transform these chemicals, leading to an even higher number of chemicals in the water cycle. Current treatment solutions are not adequate to protect human and environmental health because they rely on chemical-by-chemical assessments and regulations that rarely consider complex mixtures. Moreover, approaches that help prioritize identification and treatment of the most toxic chemicals are widely missing. As a result, unintended, adverse environmental and human health impacts of treatment or regulation decisions often become evident long after populations are exposed to toxic chemicals. There is a pressing need for approaches that identify and subsequently treat those chemicals that are of highest concern for human and environment health. In this seminar, I will discuss how novel approaches, such as reactivity-directed analysis (RDA), enable the prioritization and identification of toxic chemicals in complex mixtures. Together with mechanistic studies investigating chemical transformation mechanisms, these approaches can help characterize the formation of toxicologically relevant transformation products and support treatment design to minimize their formation.